The present invention relates to a plasma processing method of processing the surface of semiconductor devices, and more particularly to such a plasma processing method suitable for etching of a silicon nitride film.
A method using plasma is widely employed to work or process semiconductor devices. In the prior art, as the plasma used to etch a silicon nitride layer, plasma of a mixed gas of fluorine-containing gas as a main component with hydrogen-containing gas and oxygen-containing gas is utilized as disclosed in U.S. Pat. No. 5,756,402.